sandp Wall St. ''500,'' letter-perfectly Stock stat source, for short Rating service, for short It first passed 2014 in 2014, briefly Dow cousin, briefly Dow alternative "500" initials "500" index that hints at this puzzle's theme ___ 500 (Stock index) Market yardstick, for short ___ 500 (Wall St. index) 500 managers, for short? Wall St. "500" "500" initials on Wall Street Wall Street index, for short Dow cousin Wall St.'s "500"